Disproportionation of rosin



3,377,334 DISPROPORTIONATION OF ROSIN Joseph James McBride and CharlesGlenn Wheelus,

I Panama City, Fla., assignors to Arizona Chemical Company, 'acorporation of Delaware No Drawing. Continuation-impart of applicationsSer. No. 496,674, Oct. 15, 1965, and Ser. No. 560,845, June 27, 1966.This application Sept. 16, 1966, Ser. vN0. 579,817

7 Claims. (Cl. 260-98) ABSTRACT OF THE DISCLOSURE 'Disproportionatedrosin of improved color is obtained by heating, at disproportionatingtemperatures of about 180-350 C. and for a time sufficient to reduce theabietic acid content to a desired low figure below 15%,

wherein aryl, R, and the subscripts m', n, p and x are as hereinafterdefined.

This application is a continuation-in-part of applications Ser. Nos.496,674, filed Oct. 15, 1965, and 560,845, filed June 27, 1966, both nowabandoned.

This invention relates .to the disproportionation and bleaching ofrosin, including tall oil rosin, wood rosin, gum rosin, crude materialsand mixtures containing any of the foregoing, and in general, abieticacid-containing materials. Rosin mixtures include any of the mixtures ofabietic acid with tall oil or tall oil fractions containing variousproportions of rosin and fatty acids.

Rosin is widely employed in the manufacture of paper size, ester gumsand synthetic resins, protective coatings, adhesives, printing inkvehicles, greases and foundry supplies, emulsifiers for disinfectants,insecticides and other soap and chemical supplies, and in rubberpolymerization and compounding. The main constituent of rosin is abieticacid and isomers thereof, including neoabietic, levopimaric, palustric,dihydroabietic, dehydroabietic, pimaric and isopimaric acids.

'Since the conjugated double bonds of abietic acid render the rosinsensitive to oxidation, it .has become important for commercialacceptance of the rosin that the abietic acid content be reduced aslowas required for stability of the particular formulations andderivatives prepared from the rosin. This is commonly achieved bydisproportionationthe displacement of hydrogen in the abietic acid ofthe rosin to convert the same into isomeric acids, particularlydehydroabietic acid, which ICC tion process which does not require theremoval of the disproportionation catalyst from the treated rosin andwhich is more economical since the disproportionation catalyst may beemployed in substantially smaller amounts than has been heretoforeattainable.

Another object is to provide rosin having a substantially reducedcontent of conjugated unsaturated acids of the nonbenzenoid type,particularly abietic acid.

These and other objects, features, and advantages of the invention arefurther detailed in the description which follows.

Accordingly, it has now been discovered that these objects are achievedby a disproportionation process which comprises heating rosin in thepresence of an effective amount of a treating compound.

The treating agents may be represented by the general formula:

(H 0 I f I t at? inclusive. Preferred aryl groups are those containing 6to 18 carbon atoms inclusive, typically phenyl, naphthyl and anthracyl.Typical cycloalkyl groups contain -3-8 carbon atoms in the ring, e.g.,cyclopropyl, cyclopentyl and cyclohexyl.

In Formula I when aryl is phenyl it will be apparent that when p is 0the sum of m and n on .each phenyl ring will not be more than 5 and whenp is 1 or 'higher the sum of m and n on each phenyl ring will not bemore than 4. It will also be apparent, however, that the sum of n and mmay range higher when aryl is naphthyl or anthracyl since when p is 0 orat least 1 more than 5 or 4 sites, respectively, are available for OHand R substituents. The values for m, n, x and, p, except when 0, arepositive, whole numbers.

Included are compounds and position isomers having R groups of mixedcharacter, i.e., the R group or groups on one aryl ring may differ fromthe R group or groups on the other aryl ring; m and n may be the same ordifferent for each aryl ring; and when more than .one R group is presenton an aryl ring, such groups may be identical or different.

The term treating agent or treating compound, or like term, is intendedherein to mean compounds defined by Formula I above.

From the repeating unit of Formula I above it will be seen that theinvention includes not only the use of thiobis compounds (p equals butalso higher molecular weight materials, for example, where p is 100 ormore, provided sufiicient sites are available for polymerization, e.g.,the sum of n and m where aryl is phenyl does not exceed 4. The upperlimit of molecular Weight is dependent only upon how the compound ismade, e.g., Whether the material is sufiiceintly fluid in the reactionmedium for polymerization to continue, and upon use conditions, e.g.,whether the material can be effectively admixed or blended for goodcontact with the material to be bleached. Obviously, a polymer of suchhigh molecular weight as to be unmanageably tacky or glassy is to beavoided in the practice of the invention. From the viewpoint of economyand ease of preparation and use according to the invention, preferredtreating agents are those which are soluble in the material treated,e.g., compounds of Formula I wherein p is in the range of to about 20.

As typical and non-limiting examples of the treating agents may bementioned:

Thiobis napht-hols, e.g.,

1 ,1 -t hiobis B-naphthol) 2,2'-thiobis (ix-n aphthol) 2,2'-t-hiobisphenols, e.g.,

.2,2-thiobis (4-methyl-6-tert.butyl phenol) 2,2'-thiobis (4,6-dimethylphenol) 2,2'-thio'bis 4,6-di-tert.-butylphenol) 2,2-thiobis(4-ethyl-6-terL-butyl phenol) 2,2'-thiobis 4-n-propyl-6-amylphenol)2,2-thiobis(4-methyl-6-n-octylphenol) 2,2-thiobis(4-amyl-6-tert.-octylphenol) 2,2-thiobis 4-methyl-6-n-decylphenol)2,2-thiobis (4-methyl-6-laurylphenol) 2,2-thi-obis [4-methyl-6(l-methylcyclohexyl) phenol] 2,2-t-hiobis [4-methyl-6- (l -methylbenzylphenol] -2,2-thiobis (4-methylphenol) 2,2-thiobis (6-tert.-butylphenol)2,2'-thiobis( 4,6-dilaurylphenol) 2,2-thi-obis(4,6-distearyl phenol)3,3'-thio'bisphenols, e.g.,

3,3-thiobis-[methyl-6-(1,1,3,3,-tetramethylbutyl)phenol]3,3'-t-hiobis-(methyl-6-t-dodecylphenol) 3 ,3 '-thiobis(pentadecyl-t-butylphenol) 4,4'-thiobis phenols, e.g.,

4,4'-thiobis( 3-methyl-6-tert.-butylphenol) 4,4'-thiobis 3-methyl-6-( l-methylcyclohexy l) phenol] 4,4-thiobis( 2-methyl-6-tertwbutyl phenol)4,4'-thi0bis( 3,6-dimethyl phenol4,4'-thiobis-(3,6-di-tert.-butylphenol) 4,4'-t-hiobis3-ethyl-6-tert.-butylphenol) 4,4'-thiobis 3-n-propyl-6-amyl phenol)4,4-thiobis( 3-methyl-6-n-octylp'henol) 4,4-thiobis(3-amyl-6-tert.-octyl phenol) 4,4'-thiobis 3-methyl-6-n-decylphenol)4,4'-thiobis 3-methyl-6-laurylphenol) 4,4'-thiobis 3 ,G-dilaurylphenol)4,4-thiobis( 3 ,fi-distearyl phenol) 4,4'-t hiobis 3 -methyl6- (.1-methylcycl-ohexyl) phenol] 4,4'-thiobis [3 -methyl-6- l-methylbenzyl)phenol] 4,4'-thiobis(2-tert.-butylphenol) 4,4'-thiobis 2-methyl-6-l-methylcyclohexyl) phenol] 4,4 thiobis [2-mcthyl-6-( l-methylbenzyl)phenol] 4,4-thiobis(2-methyl-6-tert. butylp-henol) 4,4'-thiobis(2-tert.-butylphenol) 4,4-thiobis 2-met'hyl-6-lau ryl-phenol) 4,4-thiobis2,6 distearylphenol) 4,4'-thiobis 2,6-di a-methylbenzyl) phenol] 4,4"-thiobis [2,6-di( a,u-dimethylbenzyl) phenol] 4,4"-thiobis 3a-methylbenzyl 6- (a,a-dimet-l1ylbenzyl phenol] Thiobis-polyhydroxycompounds, e.g., 4,4-thiobis(resorcinol), 5,5-thiobis-(pyrogallol), thediand trithiobis variants of any of the foregoing, and higher molecularWeight materials corresponding to the repeating unit of any of theforegoing. These and other like compounds are disclosed, for example, inUS. Patents 2,670,382, 2,670,- 383, 2,841,619, 3,060,121, 3,069,384,3,157,517, 3,211,794 and Compt. rend. 198, 1791-3 (1934), saiddisclosures being incorporated herein by reference.

Particularly preferred are the polyhydroxy compounds such as44-thiobis(resorcinol) and 5,5-thiobis(pyrogallol), the so-calledhindered thiobisphenols, i.e., those wherein each aromatic ring issubstituted by one hydroxy group, one bulky group, e.g., secondary ortertiary alkyl group, and one short straight chain (C -C alkyl group,and higher molecular weight compounds wherein p is in the range of 5 to20. Typical of the hindered thiobis phenols are2,2-thiobis(4-met-hyl-6-tertiary-butylphenol); 4,4-thiobis(6-tertiarybutyl meta cresol); and 4,4'-thiobis- (6-tertiary butyl ortho cresol).Of the thiobisphenols, the first shows best results and it has beenobserved that as the sulfur atom is shifted away from a position orthoto the hydroxyl and the methyl group is shifted toward the ortho fromthe para position, efficiency decreases. Typical of the higher molecularweight compounds is poly[thio- (res-orcinol)] wherein p is 6 to 9.

The conditions for disproportionation and bleaching will vary dependingon the starting rosin material and the degree of disproportionationdesired. The disproportionat-ion may be carried out at a temperaturebetween 180 C. and 350 C. Tall oil rosin effectively disproportionatedby heating the rosin in the presence of the treating compound at fromabout 250 C. to 350 C. for from about 1 to 8 hours, wherein the longertimes correspond to lower treating temperatures and vice versa.Preferred ranges are from about 290 C. to 320 C. for from about 3 to 6hours.

By effective amount of the treating compound is meant sufficientconcentration of the additive to provide catalytic formation of theoxidatively insensitive isomers of abietic acid. The amounts of theadditive may be further described as minor or catalytic amounts, rangingfrom about 0.01% to 1.0%, preferably 0.1% to 0.5%, by weight of therosin. By operating with concentrations of catalyst at the higher end ofthe range and extending the time of treatment, disproportionation can beeffected at lower temperatures, e.g., in the range of about 200 C. to250 C. However, in all cases, the conditions of treatment will begoverned by considerations of economy, i.e., conditions effective forreasonably fast rate of dis proportionation while avoiding conditionswhich will cause degradation of the rosin, such as extreme temperatures.

The degree of disproportionation may be controlled as desired and asdictated by the degree of stability required in the end use. Generally,the abietic acid content should be reduced to less than about 15% byweight of the rosin and preferably to the more commercially acceptablelevel of less than about 5%, same basis. Reduction of abietic acidcontent can be followed during the reaction by sampling and analysis,employing any of the procedures known in the art such as the RubberReserve (ultraviolet) method or, preferably, by gas-liquidchromatography.

Sequence of admixture of the rosin or rosin mixture with the treatingagent is not critical. Likewise, the rosin may be heated to the desiredtemperature before the treating compound is added or rosin and additivemay be first admixed, followed by heating. The process may be conductedat atmospheric, subatmospheric or superatmospheric pressures withcorresponding variation in temperature and time of reaction. Also, theprocess may be batch, semi-continuous or continuous and mixtures ofthiobis compounds are useful.

To avoid oxidation, the treatment is generally conducted under a blanketof inert gas such as nitrogen, carbon dioxide, steam and the like.

The disproportionation and bleaching achieved by the method of theinvention are surprising results since the effects are simultaneous andit would not be expected that the treating compounds, some of which areknown antioxidants, would be disproportionation catalysts as well asbleaching agents. In this regard, the invention is distinguished fromthat of copending application Ser. No. 579,- 819 filed Sept. 16, 1966,which describes bleaching of rosin compounds with the treating compoundsin that the TABLE I I Example Feed Product Feed Product TBP, percent...0.1 0. 4 Abietic Acid, percent 30. 5 3. 0 30. 5 l. 7 Color X 4A 2A 3AEXAMPLES 3-4 Table II reports the effect of treating the same type talloil rosin as in Examples 1-2 employing the same thiobisphenol andfollowing substantially the same procedure except that heating was at350 C. for a total of 2 hours.

conditions of treatment in the latter case are less strin- The reactionmixtures were sampled each half hour for gent and involve little or notransformation of abietic acid lor nd abietic acid determinations, thelatter by UV. as compared with the pres nt invention wh n a t Initialabietic acid content Was about 27% and initial color was Y. The examplesshow very rapid disproportionation and bleaching at this more elevatedtemperature.

TABLE II Example 0.1K TBP 0.5K TBP Time, Hrs.

Abietic Acid Dehydro- Abietic Acid Dehydro- Percent abeitic Acid ColorPercent abietic Acid, Color Percent Percent 2.6 31.8 3A 1.2 -34.7 2A 1.0 33.8 WG 0.8 33. 9 X 0.7 36.6 WG 0.7 35.3 X 0. 7 36.1 WG 0.8 36. 2 WWacid is reduced to less than about 15% by weight of EXAMPLES 5-6 therosin. In essentially the same manner as in Examples 14, The followingexamples further illustrate the invention the same type rosin was heatedat 300 C. with 0.2% but are not limitative thereof except as indicatedin the of the thiobisphenols indicated in Table III for 6 hours appendedclaims. All parts and percentages are by weight with sampling after each2 hours for acid and color analunless otherwise specified. yses. Gooddisproportionation and bleaching resulted in each instance.

TABLE III Time, hours, Abeitic Acid, Dehydro- Feed Percent- 31.2 abieticAcid, Color, Y

Percent Example 54,4-thiobis(6-tertbutyl-meta cresol) 2 9. 4 22. 4 6A 47.1 41.4 6A 6 3.3 32.5 6A Example 64,4-thiob1s(G-tert-butyl-orthocresol) 2 9.0 24. 0 6-A7A 4 6.1 30.7 6A-7A 6 3.0 33.1 5A

EXAMPLES 1-2 EXAMPLES 78 g g gzify i ;3? based on reactions conductedTable IV below demonstrates eifective disproportion- To a suitablereaction vessel was chargedtall oil' rosin fi g g i i fi l 9 iconforming to the Naval Stores Act (Feb. 8, 1952) and 94 tt a 9 i Ion 0yplca ana i Federal Specification LLLR6266, Class C (May 27, fi 0 a y orosm aclds j ,msaponb 1957), except for less bottoms content. To thiswas added a and parts Of,the m type rosln 1n the indicated amount ofTBP, i.e., 2,2'-thiobis (4-methyl- Ples 8 f 1S a Crude tall 011dlstlnate @bbutYlPhenoD The mixture was then heated at having theindicated analysis. Temperature of treatment for 5 hours. The data showseffective disproportionation was 3000 w 02% of Y y and bleaching.Abietic acid content was determined by P Was employed in each p andtreatment UV a d th ol are b d on th entio l F h was effected under acover of steam rather than nitrogen. scale wherein 4A represents fourgrades lighter than X Good disproportionation resulted in bothinstances.

and 3A is one grade lighter than 2A.

GLC refers to a gas-liquid chromatographic analysis.

TABLE IV Example Feed 2 Hrs. 4 Hrs 6 Hrs. Feed 2 Hrs. 4 Hrs. 6 Hrs.

GLO Analyses:

Olelc Acid, percent 25. 7 31. 3 32. 6 33. 6 26. 28. 7 28. 4 31. 6Linoleic:

Conjugated, percent 7. 0 12. 10. 5 8. 3 6. 1 11. 1 0. 3 8.1Non-Conjugated, percen 20. 9 7.2 4. 9 4. 4 20. 1 8.0 5. 9 5. 0 AbieticAcid, percent 12.1 0.5 0.0 0.0 12.7 0.5 0.0 0.0 Dehydroabietic Acid,percent 9. 9 24. 0 23. 2 2s. 2 8.6 21.2 24. 7 25. 4

EXAMPLES 9-15 EXAMPLES 19-20 r h Exam les l-6 and the ggg g 2a 5; gi w PY y Example 19 of Table VII below show comparanve results when the roslntype of Example 1 is disproportionphenol) were charged to a 1000-ml.3-neck flask equipped with a gas inlet tube, thermometer, agitator andcondenser. The temperature was raised to approximately 200 C. undernitrogen and then steam substituted for the nitrogen. Thedisproportionation was carried out at the temperature and concentrationsnoted in Table V. The reaction was sampled periodically anddisproportionation followed by UV analysis. Good disproportionation andbleaching is evident from the results (shown in Table V).

ated by heating for 6 hours with the thiobisphenol (TBP) of Example 1and when disporoportionation is attempted under the same conditions withthe known antioxidant MBP, i.e., 2,2 methylenebis (4methyl-6-tert-butylphe- 1101). Good disproportionation over the control(rosin heated under same conditions without additive) is evident in thecase of treatment in the presence of TBP but essentially no benefitresults when MBP is employed.

TABLE V 'lempcra Concentra- Time, AbieticAc-id, Dehydro- Example ture.0., tion percent Hours percent, 30. 2 Abietic Acid, Color Y Feed percent9 310 0. 1 2 3. 1 6A 4 1. 5 4A. 5 1. 3 4A 10 .4. 300 0. 1 2 6. 1 6A 4 3.3 6A 6 2. 3 4A 11 300 0. 4 1 5. 6 6A 3 2. 2 5A 5 l. 6 3A 6 1. 6 3A 12300 0. 2 1 9. 3 7A 3 3. 5 (SA-7A 5 2. 5 6A-7A 6 1. 7 6A 13 285 0. 4 g

(l 4. 1 26. 7 (SA-5A 14 350 0.1 A 2. 8 34.6 3

1 1. 1 36. 7 VVW-W G 1% 0.8 39. 8 2 0.8 39. 2 WW-WG 15 350 0.5 *0 5.926.7 611. 1. 2 34. 7 2A 1 0.8 33. 9 X 1% 0. 7 35. 3 X 2 0. 8 36. 2 WW*Sample taken as soon as a temperature of 350 C. was reached.

EXAMPLES l6-18 Since MBP has the same structure as TBP except for CH inplace of S, the data demonstrates the surprising character of theinvention.

Example 20 of Table VII shows good disproportionation when a rosinsample having substanitally the same typical analysis as that of Example1, except for presence of some bottoms material is treated as in Example19. It will be noted in each example that the rosin was bleached TABLEVI Concentra- Abietic Dehydra- Example Temp, tion, Time, Acid, abieticColor 0. percent hours percent Acid,

percent Feed 14.0 K 1B-Gum Rosin 300 0.1 2 3. 9 2t). 3 N I 5 2. 4 22. 2N

Feed 42.6 M 17-W00d Rosin 300 0.1 5

5 2. 3 27. 6 W G-N Feed. 29. 9 20.2 13 1 3111 011, s1 Rosin 210 0.1 2 g?9 as well as disproportionated. Colors are based on the french scalestandards and abietic acid analysis was by ultraviolet analysis.

EXAMPLES 21-26 Substantially as described in the foregoing examples,commercially available tall oil rosin was heated with TBR, i.e.,4,4-thiobis(resorcinol), under the conditions and with the excellentdisproportionation and bleaching shown in Table VIII below. Initialabietic acid content, dehydroabietic acid content, and color are shownas feed. Analyses were by ultraviolet (UV) and gasliquid chromatography(GLC).

TABLE IX Analyses Example Time, hrs. Color Abietic Acid, DehydroabieticPercent Acid, Percent;

27 2 6.9 19. 4 4 4. 4 29. 7 6 4A 2. 9 32.1 28 2 5. 6 31. 9 4 2. 6 35.1 6X 1. 6 34.1 29 2 7A 9.5 25. 3 4 7A 4.9 30. 4 6 6A 2. 9 35. 2 30 2 6A 6.029. 6 4 6A 2. 6 31. 2 6 4A 1. 3 39. 2 31 2 7A 9.8 23. 2 4 6A 4. 6 30. 26 6A 2. 6 33. 2

An important advantage of 4,4'-thiobis(resorcinol) and poly[thio(resorcin0l)] over the hindered thiobisphenols, e.g., TBP, is shown byExamples 21-31 above. This is the effective disproportionation andbleaching achieved by treatment with the resorcinol compounds ofExamples 21-31 at substantially lower concentrations (0.02%) than in thetreatment with the hindered thiobisphenols (0.1)%. Moreover, for reasonsnot fully known, there appears to be an essential ditference betweenbleaching and disproportionation since the lower treating temperaturessuitable for bleaching, e.g., 200 C., do not provide appreciabledisproportionation (although acceptable for some end uses of theproduct) over the disproportionation achieved by heating in the absenceof treating agent.

TABLE VIII Analyses Example TBR, Percent Temp. C. Time hours Color UVGLO Abietic Acid, Dehydroabietic Abietic Acid, Dehydroabietic PercentAcid, Percent Percent Acid, Percent *Typical analysis.

EXAMPLES 27-31 We claim: (A) Preparation of poly[thio (resorcinoln 1. Amethod of disproportionating a rosin comprising To a solution ofresorcinol in dibutyl ether is slowly added sulfur dichloride. Thetemperature is held at 10- 15 C. for a half hour after the addition anda polymeric black precipitate forms. Sodium hydroxide solution is thenadded to dissolve the precipitate and the dibutyl ether is stripped bysteam distillation. The polymer is thereafter precipitated by additionof hydrochloric acid to the residual aqueous phase and is collected 'byfiltration as a material medium tan in color.

The number-average molecular weight is 1250, corresponding to 8repeating units (p equals 6 in Formula I above) and elementalcomposition is in the ranges C 41.58-46.12%, H 2.97-3.39%, S 21.34-25.06ash 3.2- 4.7%.

(B) Disproportionation and bleaching Essentially as described in theforegoing examples, commercially available tall oil rosin was heated at300 C. under a blanket of steam with 0.02% by weight of the polymericproduct of part A above. Table IX below shows simultaneous excellentbleaching and disproportionation as compared with a typical feed inwhich the color was in the range X-Y, abietic acid was 30% anddehydroabietic acid was 15%. The abietic acid and dehydroa-bietic acidanalyses were by ultraviolet.

heating said rosin until the abietic acid content is reduced to lessthan 15% at a temperature of about C. to 350 C. in the presence of about0.01% to 1% of a phenol sulfide of the formula:

2. The method of claim 1 wherein said phenol sulfide ispoly[thio(resorcinol)] wherein p' is in the range 5 to 20.

3 The method of claim 1 wherein said phenol sulfide is4,4-thiobis(resorcinol).

4. The method of claim 1 wherein said phenol sulfide is 2,2'-thiobis4methyl-6-t-butylphenol) 5. The product prepared by the process of claim1.

6. The process of claim 1 wherein said heating is continued until theabietic acid content is reduced to less than 5%.

7. The product prepared by the process of claim 6.

References Cited UNITED STATES PATENTS 3,157,517 11/1964 Tholstrup eta1. 99--l63 3,211,794 10/1965 Cofiield 260609 3,25 3,042 5/ 1966 Worrell260-608 3,281,473 10/1966 OShea 260609 FOREIGN PATENTS 294,526 9/1929Great Britain. 512,304

4/1955 Canada.

12 OTHER REFERENCES Tall Oil and Its Uses, published by F. W. Dodge Co.,a division of McGraw-Hill, Inc., 1965, pages 1l'l4 relied upon, copyavailable in Group 140.

Varnish Constituents, written by H. W. Chatfield, page 41 relied upon,copy available in Scientific Library, Call Number TP 938.c53 (1953).

Catalin Corporation of America, Technical Bulletin, Antioxidants CAO-4and CAO-6, Published May 1963, pages 1-7 relied upon, copy available inGroup 140.

Encyclopedia of Chemical Technology, volume 11 (1953), pages 796799relied upon, copy available in Class 260, Subclass 24 or 97.

Lovibond Tintometer, bulletin of Hayes G. Shimp, Inc., Page 17 made ofrecord, June 2, 1967.

DONALD E. CZAJA, Primary Examiner.

F. MCKELVEY, Assistant Examiner.

